Insulating or wall board product



Patented Aug. 1, 1933 INSULATING OR WALL BOARD 2 PRODUCT Carroll E. Carpenter, Western Springs, 111.; signor, by mesne assignments, ,to United States" Gypsum Company, Chicago, Ill z, a Corporation of Illinois No Drawing. Applicatioir-August 23, 1928' Serial No. 301,701

3 Claims. 01. -92-'-3) My invention relates to fibre products and more especially to pulp or fibre insulating or wall board products or allied products.

Certain varieties of trees and plants have here- 5 tofore been employed in the manufacture of such pulp or fibre products with varying degrees of success. In the production of fibre or pulp products of this nature it is essential that the raw materials, when reduced to pulp form, shall have .10 certainqualities largely measurable by the freeness of the pulp which will permit conversion to board at proper speeds on the various types 'of board forming machines available, and will, at the same time, give a product which, due to the v cellular construction of the composite mass,'will have the requisite degree of strength, flexibility, and insulating qualities. The product thus formed also should be such that it can be effectively sized or otherwise rendered water resistan during or after manufacture.

One object of my invention is to provide a pulp or fibre product which is well suited to thefmanufacture of relatively thick boards having'a' generally open or cellular structure, possessing a relatively high insulating value; as well as providing a board which is both light and strong with good nail-holding qualities and which is easy to cut and handle.

Another object of my invention is the provision of a fibre product having all or most of the above characteristics and made either from hard wood alone or from suitable admixtures of hard and soft woods. By the term hard Wood it is meant to include such hard textured woods as are typified by the following group:

By the term soft wood it is meant to include such soft textured woods as are typified by the following group:

(Taxodium distichum) Cottonwood (Populus deltoides) Willow (longleaf) (Salim fluviatilz's) Among the above mentioned varieties of trees, some are found in abundance particularly in the southern part of the United States and, while 50 Cypress readily accessible and relatively low in price, have not been heretofore usable for the purposes here in set forth nor has it been possible up to the present timeto'fully utilize their value in other ways. The problem-,-therefore, has beenlto render these woods P available for useful purposes.

i After carrying out a number of long iand-costly experiments, I have succeededin the production'of a product-suitable forsinsulating and wall board by'utilizin'g woods'ofthe'types above set forth." c

When h'ard woods which have a dense formation, comprising relatively short fibres, are used alone in the manufacture of wall board it is preferable to lightly cook such wood either with plain water or with a chemical solution, such as,

for example, a mild caustic or acid solution, be-

gree of freeness' that will permit proper'formation of a wet board cake on a board forming machine. Example 1.-'-As an example of one method by which suitable hard wood pulp may be produced,

the hard wood is -prepared in the usual manner by' chipping or reducing in other manners to suitable dimensions to permit proper contact, circulation, and penetration of the cooking liquor. The wood in this form is next cooked either with plain water or with a mild caustic or acid solu tion for from 1 to 6 hours. The cooking may be conducted either in an open vessel or in a closed vessel under pressure. When the wood has been properly cooked it is next transferred to a grinding or reduction mill, which may be of a more or less conventional form such as, for example, a

, Bauer grinding mill, a Bird refiner, a rod mill,

a stone wood pulp 'grinder, a hammer mill, a shredder, disintegrator, etc.

Wall board, when formed from hard wood pulp alone, made in accordance with the above process, is in the form of a relatively light, firm and stiff sheet having good nail-holding properties and a relatively high insulating value. This sheet, however, while suitable and preferable for certain uses, is inclined to be brittle and relatively inflexible and modifications are necessary for board to be used in other fields.

For the purpose of obtaining a greater degree of flexibility of the sheets formed from hard wood pulp, it is desirable to mix with the hard wood pulp varying proportions of soft wood pulp, or soft wood pulp mixed with other vegetable fibres and flexibility oftheproducte .-:r- 1

'chine used.v The freeness of each pulp can. and g1 'lindrical vessel having a diameter of -.9 inches,

2 ,920,496 having characteristics which will give to the board stock has a suitable freeness as previously exincreased strength and flexibility. plained, after which it is formed into board in Example 2.-As an example of this method of the usual manner.

producing pulp, the hard wood is ground or dis- Example 4.The hard wood and soft wood integratedeither with or without the prelimin'ary pulpsl are s sreaes in the abet examples by cooking, the'grir'iding' or disintegrating being so grinding or disintegrating," either withmr withconducted as to produce relatively short; hy-- out preliminary cooking. These pulps are then drated fibres. The soft wood is ground or disin mixed and to the mixture is added a quantity of tegratecl without cooking so as to produce rel'a-- from 5% to 25% of true chemical pulp such as tively long fibred pulp, after whichiahehardgandfs l mit-or ,sulphite, orepulp mill tailings, screensoftwood pulps are intermixed in varyingproporings, or suitably prepared vegetable fibres such tions. The intermixed pulp, is'theri'; delivered to fas'cornstalks; straw; grasses, etc. Pulp characthe board forming machine.'.and fiforx'neddntof, reregemg list being composed of board. The soft wood fibres, being of remit/en" relatively longl'fibre's or fibre bundles makes posgreater length than the hard wood fibres bring sible the prciduction of a suitable board even to the board an increased degree ofi fiexibilityw-whemthelhard anddsoft wood pulps have a preand strength which, for some purposesf'ren'de'rspohderance of relatively short fibres and fibre it more easily handled with less danger -ofpreakm bundles. ing when bent. While mixtures of one part each Example 5.-The hard wood pulp is prepared of hard and soft wood .pulpsonthe-:basesmf, dry as bathe above-examples .by mechanic al reducfibre is found suitable, these proportions maybe ition eitherwithorwithout preliminary. cooking varied froma-mixture containing agsmalhperand, instead of mixir rg infa quI I 1 ifiy 0 Ql i$ centage ofsoft=wood and a high percentage-of s0t-,wood,,the;,hard meapmem t emmed hardwood. to a mixture -containingia small peralone with f r9 m ,5% .to, 25%.' of true' chemical centage of-hard rwood and'arhigh percentage of 19;Q-ll 1m lljl lg fseifeefi fi e 19. su t bly soft wood withoutseriously affecting-thev strength prepared vegetablafibre. flfhisfmixture is hen I formed; into, a-f -i'ri thefufsual'uianite iflin The'hard' and-soft wood.pulpsrwhichiare-to this productio a d ,WOQ be intermixedtshould preferablypbut not necessboardhavin sarily, vary in freeness to get the desired results. oi -itshnorous, structfir'Qa iQ iI {i Qfi Therhard wood pulp may-be either-'more or less ing. con ipos ed, ghostly of llon ilfipres free than =the.soft woodpulp andthishvariance .b ndl s aetsitotefie iiiely, of freenessmay be; extended. considerably in fibres togetheriand gives the board either direction so: long as-ther'freeness of the and flexibility ..and prevents it r'onrbe mixture isrwithin certain limits defined -by the brittle.

proper functions of the particular formingma- The "'ulpmixtu res as de s cri I ,ven examples are mixed withrwafterinthfe usual will 'be varied depending on thegproportionsof -ma1 to t th d si d".(i'0115i ll ifi' id l' the two'woods used in mixture.v formed o boa dn'any' 'suitablebba df q ni ne In order to define the degree of .freeness suit- .machinesuch asthe Oliver typeor the liour- Hi5 able for the pulp mixture,- for-therpurposeshere- ,crimer type, d fe theip liimin i emay in set forth, the following-{dataisgiven. Acye suitaplyfsi dfto, render i WatetrrQM-j and a height of 8 inches pr0vided-;with='a ,'60 .,specifia tion afl .in' ,th' claimsis tend no mesh screen at its bottomis used forthe recep- 2 yl fl f, th div du l fibl SQ j @180 0 tionof the suspended pulp: The .mixture- .is q e i Q-P D Db w e fll eil th 3 1 C made up so as to-give a consistency of substanre bu dles.

tially 1%; Thisreceptacle;is.then.filled.to the The.use of the term board inthis speciflcatop with the pulp and water -mixture-at a temperature of approximately 70 F. The bottom of the receptacle is provided with a suitable ,arrangement for-attaching a suctionpurnpthereto and after the stock has been poured in, it .is subjected to a suction equivalent to approximately 26 inches of mercury, For the stoclrto have a suitable freenessitshould'be such that tion and in the claims isjinten'dedto coverf'any form of article into which the pulp'is made 'with-125 out regard tothe thickness or, other dimensions ,thereof.

The present invention thus provides/a wall board or analogous composition, in which vary ing proportions of hard wood pulp and soft wood" pulp may be utilized and in which the proportions substantially all the water will be drained or of it er pulp may predominate-v if desiredsucked out in about..65 seconds. Howeventhe Where fieXibiliW andL g strength are necestime in seconds for draining. may vary from 50 sary considerations these characteristics of'the to without materially afiecting thefdrinaboard may readily b'e inc ea by- 't use f' tion of the board on the board'forming'niachine. long fibred soft wood pulp or by the addition of Certainof these factors may vary wi'thin sublong and tough fibred chemical pulp, tailings, stantial limits without affecting the formation screenings or vegetable fibres. The freeness of of the board on the machine. Thus if the freethe stock is so controlled that a board offa maxiness as represented in secondsis altered so that mum strength may be f ormed with a minimum the stock is slower, the temperature and suction amount. of time..,on an ordinary, boardforming could-be correspondingly changed to compensate for the difference in freeness.

Example 3.-The hard wood is-ground or disintegrated, as inEx-a'mple 2, either with or without preliminary cooking and the softwoodtobe mixed therewith is first-cooked from 1 to 6 hours machine. The product thus produced is of a generally open porous construction, havingrelative'ly high insulating value, with good nail-hold-, ing qualities andis'relatively easy-to cut'and' handle without undue danger of breakage during handling and then ground or disintegrated.- The pulps Having describedmy invention, I 'clairnf thus formed are then mixed in proportions, such as given above under Example 2, so that the 1. A fibre board of substantial thickness, high insulating value and cellular structure, comprising a; mixture of relatively short, hard wood the hard. and soft wood fibres are in approxifibres from the group of woods:,-oak, gum, tupelo, mately equal proportions.

. hackberry, magnolia, elm, maple, birch, beech, 3. A fibre board as defined in claim 1 in which and" relatively long, soft wood fibres from the the hard wood fibres arelightly cooked, and the 5 group'of woods:--cypress, cottonwood, willow. 1 soft wood fibres are uncooked. 2; A fibre board as defined. in clainr 1 in whioh CARRQLL E. CARPENTER.

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